聚乙烯燃气管道电熔接头熔区应力分析

Stress Analysis of Fusion Zone of Electrofusion Joint of Polyethylene Gas Pipeline

电熔焊接是聚乙烯管道最常用的连接方法之一,电熔接头的设计对管道系统安全至关重要。电熔接头焊接界面应力分布的准确分析是电熔接头设计的基础。采用理论公式推导和有限元分析相结合的方法,研究电熔接头在内压、轴向力和温度变化作用下的应力分布情况,发现接头焊接界面应力分布呈现中间小、两边大的规律。定义端部应力集中系数为界面峰值应力与平均应力的比值,分析得到应力集中系数随熔区长度的关系,结果可为基于内压与轴向力的电熔接头熔区设计提供理论参考。

Electrofusion (EF) is one of the most common methods for connecting polyethylene(PE) pipes.Proper design of EF joint is crucial for the safety of the piping system.Accurate analysis of the stress distribution at interface of the EF joint is the basis for design of joint.In this paper,the method of combination of theoretical formula calculation and finite element analysis (FEA) was used to study the stress distribution of EF joint under variable internal pressure,axial force and temperature.It was found that the stress distributed at the welding interface was small in the middle and large on both sides.The edge stress concentration factor was defined as the ratio of peak stress to average stress of the interface.The relationship between the edge stress concentration factor and fusion zone length was obtained by analysis.The results can provide a theoretical reference for design of fusion zone length of the electrofusion joint based on internal pressure and axial force.